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-Dominant- [34]
3 years ago
9

You serve a volleyball with a mass of 2.1 Kg. The ball leaves your hand with a speed of 30m/s. The ball has __________________ e

nergy. Calculate it.
Physics
1 answer:
wariber [46]3 years ago
6 0

Answer:

<h2>The ball has kinetic energy.</h2><h2>Kinetic energy is 945 J</h2>

Explanation:

Kinetic energy = 0.5 x Mass x Velocity²

Here the ball has mass and velocity.

So the ball has kinetic energy.

Kinetic energy = 0.5 x Mass x Velocity²

Mass = 2.1 kg

Velocity = 30 m/s

Kinetic energy = 0.5 x 2.1 x 30²

Kinetic energy is 945 J

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Why is the SI system a consistent system?
Goryan [66]
S.I. System is same for all countries, so if any Scientist uses it, then another Scientist from any place around the world can figure it out, that what is he saying, how exactly is the magnitude of the object. That's why it is a Consistent system

Hope this helps!
7 0
3 years ago
Read 2 more answers
Sunlight appears white. However, rainbows, sunburn and the ability to see colors tell a different story.Explain what each of the
alexdok [17]
A) Sunlight basically consists of a combination of light of different wavelengths. Each of these wavelengths correspond to each of the colors of the rainbow. For example, red light has the longest wavelength. This is followed by orange, then yellow, green, blue and indigo. Violet has the shortest wavelength. These wavelengths (750 nm  to 400 nm) constitute the visible colors. All these light components of different wavelengths combine together to become the color white.

b) When this sunlight passes through droplets of rain, it gets refracted and that is what breaks up the white light into individual colors of the rainbow, just how light passing through a glass prism gets broken down into its individual seven colors.

c) Different objects have the ability to absorb different wavelengths of light. For example, glass absorbs light of all wavelengths except those between 560-520nm, which corresponds to green light. So it reflects the green light and thus, our eyes see  grass as green in color.

d) Light of wavelength below  400 nm (ultraviolet) and above 750nm (Infrared) are not visible. However, they exist in the sun's radiation. Ultraviolet rays are very harmful and responsible for causing sunburn and some types of skin tumors. Infrared light is also harmful and can cause premature wrinkling of skin.
5 0
3 years ago
Erica throws a tennis ball against a wall, and it bounces back. Which force is responsible for sending the ball back to Erica? t
Nutka1998 [239]

Answer:

the normal force that the wall exerts on the ball

Explanation:

As Newton's third law states:

"when an object A exerts a force on object B, then object B exerts an equal and opposite force on object A".

If we apply this law to this problem, we can identify the ball as object A, and the wall as object B. As the ball hits the wall, the ball exerts a force on the wall (toward the direction of motion of the ball), so the wall exerts an equal and opposite force on the ball (in the opposite direction). This force is the normal force of the wall, and it is responsible for pushing the ball back towards Erica.

6 0
3 years ago
Read 2 more answers
A 0.20-kg object is attached to the end of an ideal horizontal spring that has a spring constant of 120 N/m. The simple harmonic
Umnica [9.8K]

Answer:

<em>A = 6.9 cm</em>

Explanation:

<u>Simple Harmonic Motion</u>

A mass-spring system is a common example of a simple harmonic motion device since it keeps oscillating when the spring is stretched back and forth.

If a mass m is attached to a spring of constant k and they are set to oscillate, the angular frequency of the motion is

\displaystyle w=\sqrt{\frac{k}{m}}

The equation for the motion of the object is written as a sinusoid:

\displaystyle X=A\ cos\ w\ t

Where A is the amplitude.

The instantaneous speed is computed as the derivative of the distance

\displaystyle X'=V=-A\ w\ sin\ w\ t

And the maximum speed is

\displaystyle V_{max}= A\ w

Solving for the amplitude

\displaystyle A= \frac{V_{max}}{w}

Computing w

\displaystyle w =\sqrt{\frac{120}{0.2}}=24.5\   rad/ s

Calculating A

\displaystyle A=\frac{1.7}{24.5}=0.069\ m

\displaystyle \boxed{A=6.9\ cm}

7 0
3 years ago
As you may well know, placing metal objects inside a microwave oven can generate sparks. Two of your friends are arguing over th
Fofino [41]

Answer:

5.04\cdot 10^8 A

Explanation:

The work function of the metal corresponds to the minimum energy needed to extract a photoelectron from the metal. In this case, it is:

\phi = 3.950\cdot 10^{-19}J

So, the energy of the incoming photon hitting on the metal must be at least equal to this value.

The energy of a photon is given by

E=\frac{hc}{\lambda}

where

h is the Planck's constant

c is the speed of light

\lambda is the wavelength of the photon

Using E=\phi and solving for \lambda, we find the maximum wavelength of the radiation that will eject electrons from the metal:

\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{3.950\cdot 10^{-19} J}=5.04\cdot 10^{-7}m

And since

1 angstrom = 10^{-15}m

The wavelength in angstroms is

\lambda=\frac{5.04\cdot 10^{-7} m}{10^{-15} m/A}=5.04\cdot 10^8 A

3 0
3 years ago
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